1099 Misc Box 8 Income

In 2021, I received a 1099 Misc with income in Box 8.  I also paid investment interest in 2021.  I noticed the amount of income in box 8 was not included on Form 4952 on line 4a.  I think it should be and am curious why it isn't.  Thanks for your help!

 

Kind regards,

 

Chris